To find a suitable potential for the interatomic interactions in molecular dynamics (MD) simulations for the study of the mechanical properties of the nanostructured thermoelectric material CoSb 3 , the advantages and disadvantages of existing potentials for the material are first reviewed and discussed, and then an enhanced potential is proposed in which both bondstretching and bond-angle distortions are considered. The structural stability and elastic properties of the crystalline CoSb 3 model within the developed potential are validated at finite temperature using classic MD tests. Comparison of the mechanical behavior of bulk single-crystal CoSb 3 , including the stress-strain curve and configuration evolution under tension, shows that the enhanced potential exhibits better reliability than the other potentials. Finally, the significance of the potential and its possible further improvement for broader application are briefly discussed.

This paper reports molecular dynamics simulations performed to study the mechanical properties of Zn 4 Sb 3 nanofilms. In the simulations, interatomic interactions are represented by an enhanced atomic potential, and the crystal structure is based on the core structure of b-Zn 4 Sb 3 . For tensile loading along the [0 1 0] direction, the stability of the crystal structure of the Zn 4 Sb 3 nanofilms is analyzed by the radial distribution function method, and the stress-strain relation of the nanofilms is obtained at room temperature. Our present work indicates that the mechanical properties of Zn 4 Sb 3 nanofilms are quite different from those of bulk Zn 4 Sb 3 due to the impact of surface atoms of the nanostructure. From the atomic configuration, Zn 4 Sb 3 nanofilms exhibit typical brittleness. The size effect and the strain-rate effect on the extension of Zn 4 Sb 3 nanofilms are discussed in detail. Lastly, the mechanical properties of nanofilms based on different Zn 4 Sb 3 crystal structure models are examined.

Band structure and density of states (DOS) of CoSb 3 single-filled by seven kinds of atoms (R 0.125 Co 4 Sb 12 ) are calculated by the density functional method. The results for the electronic structures in turn determine the electrical transport and thermal performance. It is found that the band structure of R 0.125 Co 4 Sb 12 shows no significant changes compared with that of CoSb 3 , and the results indicate that void filling with a small quantity of R atoms does not change the bond formation in CoSb 3 . However, the partial DOS reveals that there could be interaction of Sn, Tl, In, and Yb atoms with CoSb 3 . The results for the electrical transport properties and thermal properties show that Sn, Tl, and In atoms increase the Seebeck coefficient and La, Eu, and Yb atoms are helpful for increasing the electron concentration and decreasing the thermal conductivity further. According to our calculations and Yang's principle, double-filled CoSb 3 with atomic combinations of (In, Ca), (In, Ba), (Sn, Eu), and (Sn, La) may exhibit good thermoelectric performance.

We report an investigation of the electronic structures and electrical transport properties of the single-filled and double-filled CoSb3 skutterudites with Ba, Yb and In atoms by density functional calculations and Boltzmann transport theory. The band structure and the density of states of single and double filled CoSb3 are calculated and discussed. Based on the results of the band structure, the temperature dependence of Seebeck coefficients, the electrical conductivity, the power factor and the carrier concentration are computed, which are generally in good agreement with the experimental data. The results indicate that the combination of (Ba, In) could greatly improve the thermoelectric properties while the combination of (In, Yb) and (Ba, Yb) would have negative effect on the power factors, due to the fact that the interaction of Yb atoms with CoSb3 would result in a reduction of the electron mobility.

We have fabricated metal doped PrBa 2 Cu 3 O 7 (PBCO), i.e. PrBa 2( Cu 1-x M x)3 O 7 (PBCMO) with M = Al , Fe, and Ni, and x = 0.05, 0.10, 0.15, and 0.20. X-ray data indicate no significant second phase for Ni-doped samples until 15% doping level is reached. No second phase was found in Al- and Fe-doped samples up to the 20% doping level. All the doped samples are in orthorhombic structure and their lattice parameters are very close to those of YBa 2 Cu 3 O 7-δ (YBCO). However, for Al or Fe doped samples the difference in lattice parameters a-b has decreased from that of PBCO. At 77 K the electrical resistivity for Al- or Fe-doped samples is several orders in magnitude higher than that of PBCO. Therefore these compounds may be better buffer-layer materials for YBCO superconducting electronic circuits and devices.